Variety Of Soil Types Research Articles

The Multifaceted Soils of Himachal Pradesh, India: Types and Characteristics

The soils of Himachal Pradesh face a multitude of pressing issues that threaten their health and agricultural productivity. The diverse geographical features, temperature regimes and biological zones of Himachal Pradesh have resulted into a vast range of soil types in the state. Alpine, forest, alluvial and sub-mountain soils are the four major soil categories into which the state's soils can be generally divided. Only a particular species and adapted plants can thrive in the extreme weather circumstances of alpine soils, which are located at higher elevations and possess soils having thin, stony and acidic in reaction. The mid-hill areas are dominated by forest soils which are distinguished by their high levels of organic matter and nutrients. These soils support luxuriant vegetation and make effective agricultural methods possible. Alluvial soils, which are mostly found in river valleys and are deposited by ravine systems are extremely rich and perfect in fertility and suitable for growing a range of crops including vegetables, rice and maize. Located in the foothills, sub-mountain soil exhibits a blend of traits from alluvial and forest soils, thus providing a range of uses for horticulture and agriculture. In addition to supporting a diverse array of plant and animal life, Himachal Pradesh's varied soil types are vital to the region's agricultural economy. One of the biggest problems is soil erosion, which is made worse by the steep terrain and abundant rainfall in the area. This results in the loss of topsoil and decreased fertility. Deforestation, overgrazing, and unsustainable farming methods all contribute to land degradation, which further reduces biodiversity and soil quality. Furthermore, crop development is impacted by soil acidity in high-altitude regions, which restricts nutrient availability. However, these issues need efficient conservation measures and soil management techniques. In order to maintain Himachal Pradesh's rich biodiversity and agricultural potential for future generations, sustainable agricultural development and environmental protection in this ecologically sensitive area depend on an understanding of the complex soil dynamics. Addressing these interconnected issues requires a comprehensive approach, emphasizing sustainable land management practices, community engagement, and restoration efforts to preserve the vital soil resources of this ecologically sensitive region.

Genome-Wide Identification and Characterization Thaumatin-like Protein (TLP) Genes in Wild Olive (Olea europaea var. sylvestris)

The wild olive tree (Olea europaea var. sylvestris) is the ancestor of all olive varieties, displaying remarkable adaptability to diverse climatic conditions and soil types. This iconic tree of the Mediterranean Basin stands out for its ability to withstand environmental stresses, such as water scarcity and temperature variations, playing a crucial role in the ecology, economy, and culture of the region. In this study, 42 TLP genes were characterized in the wild olive tree, distributed across 14 chromosomes and nine scaffolds. In silico analysis revealed the presence of domains associated with antifungal activity in some sequences, indicating their potential role in pathogen resistance. The structural diversity of OeTLP genes was explored through multiple alignments, conserved motifs and phenetic analysis. Correlation was observed between phenetic diversity, genetic structure, and motif patterns, suggesting different functions among OeTLP groups. Additionally, the distribution of exons and introns in the pheneticc tree provided further insights into the evolution of these genes. Comparative modeling of OeTLPs unveiled three-dimensional models with good structural quality and distinctive surface charge characteristics. This study provides a comprehensive understanding of the physicochemical, structural, and phenetic features of TLP genes in Wild Olive, contributing to knowledge about this species' response to environmental stresses and pathogens.

Numerical Modeling of Soil and Structure Behavior for Tunneling in Different Types of Soil

This note studies the correlation between surface and tunnel volume loss in various types of dry soil via finite element method. The effect of small strain stiffness, the buoyancy effect of soil, and tunnel overburden depth are considered in the 2D tunneling model. The results show that both surface volume loss ratio and settlement trough width parameter in the empirical solution can be expressed as a linear equation of tunnel volume loss ratio for 1D overburden shallow tunnels. Furthermore, the surface volume loss ratio can be presented as a non-linear polynomial equation of overburden depth and tunnel volume loss ratio in a 3D space, and this equation holds in different types of soil. The ranges of required fitting parameters and upper and lower bounding surfaces are suggested for various types of soil. Knowledge of this correlation between surface and tunnel volume loss is valuable, as it can be employed in practice for preliminary tunnel design in the absence of tunneling induced maximum ground settlement.

Biological Characterization of Geo-Referenced Soil Samples from Major Rice-Growing Tracts of Southern Kerala

A survey was conducted from January to March 2023 to assess the soil biological fertility index across five agro-ecological units in the rice-growing belts of Southern Kerala. These units included Onattukara sandy loam (AEU 3), Kari soil (AEU 4), Pokkali soil (AEU 5), Southern laterites (AEU 8), and Midland laterites (AEU 9). The study was carried out in the College of Agriculture, Vellayani Thiruvananthapuram. The survey aimed to assess microbial activity and organic carbon content, thereby enhancing our understanding of the biological fertility across these diverse soil types. Twenty geo-referenced surface soil samples @ 0- 15 cm were collected in every AEU by prescribed method. The collected samples were subjected to the characterization of soil biological properties such as dehydrogenase activity, organic carbon, microbial biomass C, microbial biomass N and soil respiratory rate following the standard protocol. The findings showed that organic carbon in AEU 5 with the highest mean value (3.03 %), followed by AEU 4 (2.19 %), AEU 9 (2.01 %), AEU 8 (1.01 %), and AEU 3 (0.56 %). Dehydrogenase activity was highest in AEU 5 (682.54 µg TPF g-1 hr-1), followed by AEU 4, AEU 9, and AEU 8, and lowest in AEU 3 (76.71 µg TPF g-1 hr-1). AEU 5 exhibited the highest microbial biomass carbon and microbial biomass nitrogen activities, while AEU 8 showed the lowest. Soil respiration was highest in AEU 5 and lowest in AEU 3. Based on these soil microbiological indicators, soils were classified into three categories: low, medium, and high fertility. The Biological Fertility Index (BFI) scores indicated favorable conditions in AEU 4 and 5, moderate in AEU 9, and low in AEU 3 and 8. By establishing a comprehensive understanding of soil biological fertility across various agro-ecological units, the research aims to contribute to improved soil health and crop productivity in the region.

Unravelling the microbiome of wild flowering plants: a comparative study of leaves and flowers in alpine ecosystems

BackgroundWhile substantial research has explored rhizosphere and phyllosphere microbiomes, knowledge on flower microbiome, particularly in wild plants remains limited. This study explores into the diversity, abundance, and composition of bacterial and fungal communities on leaves and flowers of wild flowering plants in their natural alpine habitat, considering the influence of environmental factors.MethodsWe investigated 50 wild flowering plants representing 22 families across seven locations in Austria. Sampling sites encompassed varied soil types (carbonate/silicate) and altitudes (450–2760 m). Amplicon sequencing to characterize bacterial and fungal communities and quantitative PCR to assess microbial abundance was applied, and the influence of biotic and abiotic factors assessed.ResultsOur study revealed distinct bacterial and fungal communities on leaves and flowers, with higher diversity and richness on leaves (228 fungal and 91 bacterial ASVs) than on flowers (163 fungal and 55 bacterial ASVs). In addition, Gammaproteobacteria on flowers and Alphaproteobacteria on leaves suggests niche specialization for plant compartments. Location significantly shaped both community composition and fungal diversity on both plant parts. Notably, soil type influenced community composition but not diversity. Altitude was associated with increased fungal species diversity on leaves and flowers. Furthermore, significant effects of plant family identity emerged within a subset of seven families, impacting bacterial and fungal abundance, fungal Shannon diversity, and bacterial species richness, particularly on flowers.ConclusionThis study provides novel insights into the specific microbiome of wild flowering plants, highlighting adaptations to local environments and plant–microbe coevolution. The observed specificity indicates a potential role in plant health and resilience, which is crucial for predicting how microbiomes respond to changing environments, ultimately aiding in the conservation of natural ecosystems facing climate change pressures.

Enhancing forensic applications through the mineralogy of clays in surface soil horizon: A case study of baixada fluminense, Southeast Brazil

Clay minerals possess chemical, mineralogical, and crystallographic characteristics that make them potential forensic markers, as they can reflect geochemical and weathering processes on a detailed scale. Therefore, this study aims to use the mineralogy of the clay fraction to distinguish samples from the surface soil horizons in four municipalities in Brazil, to assess the possibility of geographical tracking for forensic applications. Studies characterizing clays in environments with a variety of soil types in forensic pedology are necessary but still in their early stages. Furthermore, due to the high incidence of homicides involving the displacement of bodies in the region and the low resolution of these crimes, this research is crucial for geoscientific applications, with the potential for global replication. The samples were separated by centrifugation and analyzed using X-ray diffractometry, X-ray fluorescence, and thermogravimetry. Minerals were determined through quantitative mineralogical analyses using Rietveld and Biscaye methods. Additionally, in conjunction with the crystallographic parameters of kaolinite (Full Width at Half Maximum – FWHM), it was possible to form 8 Clay Mineral Assemblages and Gibbsite (CMAG), whose geographical delimitation considered geological and hydrographic aspects. The determination of CMAGs is based on mineralogy and is defined as follows: CMAG 1: kaolinite+(illite); CMAG 2: kaolinite+(gibbsite); CMAG 3: kaolinite + illite + montmorillonite; CMAG 4: kaolinite + illite+(gibbsite); CMAG 5: ordered kaolinite+(illite)+(gibbsite); CMAG 6: kaolinite + gibbsite+(illite); CMAG 7: disordered kaolinite + illite + gibbsite; CMAG 8: kaolinite+(illite)+(chlorite). The results indicate that the quantification of clay minerals in samples from surface soil horizons, FWHM, and the % of Al in goethite can represent valuable tools for forensic pedology. Moreover, through the characterization of iron and titanium (hydr)oxides, it was possible to distinguish samples with a distance of 335 m between them, further expanding the capability to identify the geographical origin of samples, making them potential forensic markers.

The Impact of Agricultural Inputs and Environmental Factors on Potato Yields and Traits

Potato, a component of global food security and economic stability, is cultivated extensively worldwide due to its adaptability to diverse climates and soil types. Ongoing research and technological advancements, including the use of unconventional products destined to fight the most harmful pathogens, are essential for enhancing productivity and resilience in potato farming. The current study aimed to identify the most appropriate fertilizers and phytosanitary treatments in order to attain optimal potato yields, dry matter, and starch contents, under climate-specific environments. The experiment was conducted in the northwest of Romania in 2023. The research was organized as a trifactorial experiment with the factors variety, fertilization, and phytosanitary treatment. XLSTAT (2022.2.1v.) was utilized for data processing. Mineral fertilization combined with conventional phytosanitary treatment led to the highest average yields in both potato varieties. Also, a combination of organic fertilization and treatment with 4% A. cepa extracts led to notable results, which suggests the possibility of successfully using these inputs in organic agriculture. The study shows the importance of selecting appropriate agricultural inputs to optimize potato yields, achieve specific levels of dry matter and starch content in a specific area, and promote sustainability.

Evaluation of Straw Mulch as an Erosion Control Practice for Varying Soil Types on a 4:1 Slope

Evaluation of Straw Mulch as an Erosion Control Practice for Varying Soil Types on a 4:1 Slope

Effects of initial soil moisture on rill erodibility and critical shear stress factors in the WEPP model across diverse soil types

Rill erosion, a significant issue in agricultural regions, is intricately linked to initial soil moisture conditions, affecting the development of concentrated flow erosion processes. However, understanding its dynamics amidst varying soil moisture conditions remain challenging. This study aimed to assess the impact of different soil moisture levels on rill erodibility parameters in the Water Erosion Prediction Project (WEPP) model and to evaluate soil cohesion across a spectrum of soils. Through laboratory experiments employing a small V-shaped rill channel, we investigated rill erodibility (Kr) and critical hydraulic shear stress (τcr), under three soil moisture scenarios: initially dry, saturated, and drainage, with incremental surface inflow rates. Additionally, we examined the efficiency of soil cohesion obtained from an Automated Soil Cohesion Measurement Apparatus in predicting Kr and τcr across various soil textures. Our analysis encompassed twenty soils representing nine texture classes, revealing significant correlations between basic soil properties, cohesion parameters, and WEPP model rill erodibility. Notably, initial soil moisture conditions exerted substantial influence on erodibility potentials. Soils with higher silt contents demonstrated better fits in terms of Nash-Sutcliffe model efficiency, particularly under initially dry and saturated conditions. However, predictions for initially drained soils yielded poor fits, emphasizing the intricate interplay between soil properties and hydrological conditions. In conclusion, our findings emphasize the critical role of topsoil water dynamics in rill erodibility. We propose that soil cohesion serves as a valuable predictor, complementing friction forces within the soil and enhancing simulations of rill erodibility under shallow flow conditions in rills, particularly in next-generation process-based modeling approaches.

Enhancing growth and tolerance traits in pepper (Capsicum annuum L.) through water-saving irrigation practices

Due to their intensive cultivation, horticultural crops are particularly susceptible and vulnerable to the detrimental effects of drought stress, necessitating significant water inputs for optimal growth and yield. Accordingly, water-saving irrigation strategies, i.e., Partial Root zone Drying (PRD) and Regulated Deficit Irrigation (RDI) emerge as pivotal tools for bolstering the resilience of the horticultural sector. The current study aims to evaluate the impact of PRD and RDI strategies on pepper (Capsicum annuum L.) growth, and physio-biochemical attributes under semi-controlled greenhouse conditions. Research findings revealed pronounced enhancements in stem length under both irrigation strategies, with PRD exhibiting superior effects on shoot fresh and dry biomass (increases of 57.2% and 61.1%, respectively) compared to full irrigation. At the physiological level, PRD and RDI induced a significant reduction in stomatal conductance in pepper plants relative to full irrigation, while maintaining leaf water potential and relative water content. Biochemically, plants subjected to PRD and RDI methods exhibited significant accumulation of free proline, particularly pronounced with PRD (approximately 115.9% increase compared to full irrigation). Furthermore, Chl a and carotenoid concentration significantly increased under PRD, indicating sustained photosynthetic functionality. Comparatively, PRD appears as the more effective technique, offering the potential to conserve agricultural water about 50 without compromising growth parameters, while simultaneously enhancing tolerance traits in C. annuum. Nonetheless, further investigations on other traits across diverse soil types, climates, and cultivars under field conditions are imperative to ascertain the broader applicability of PRD and optimize its implementation.

Numerical investigation of heat and moisture migration in clayey and sandy soils, exploring seasonal fluctuations

Geothermal energy is widely known as a sustainable and eco-friendly energy source. For its applications, assessing the hydrothermal soil behaviour is crucial. However, the installation of ground geothermal systems at shallow depths makes them sensitive to atmospheric conditions, which affect the temperature field and the thermal balance. This paper presents the results of a numerical study investigating the hydrothermal behaviour of unsaturated soils (clay and sand), considering the meteorological variations at the ground surface. The atmospheric-soil interactions, including solar radiation, sensible heat flux, and latent heat flux, are essential for quantifying the energy balance and the hydro-thermal transfer processes taking place at the ground surface. By analysing these components, we can gain a comprehensive understanding of how energy is distributed and transferred to the soil. A numerical study was carried out using a finite element method (FEM) to assess the hydrothermal behaviour of unsaturated soils. The analysis of the obtained results from the model simulation reveals that variations in soil types have an impact on the distribution of heat and moisture migration, with both time and depth. Moreover, it appears that clayey soils show the highest efficiency in geothermal energy transfer. This research offers crucial insights into the optimization of both the design and implementation of geothermal systems.

Taxonomic Composition of Forest Areas in Gabala District

The forest cover of the Gabala District, which is part of the forests of the southern slope of the Greater Caucasus, attracts attention with its richness and diversity of species composition. The diversity of soil types in the Gabala District, as well as the relief and climatic conditions, determine the richness of vegetation. In the south, from the mountain range bordering the Shirvan plain to the watershed peaks of the Greater Caucasus, there is a remarkable alternation of regions and zones distinguished by their diversity. The article presents the results of the study of forests in the Gabala district. As a result of taxonomic analysis, the distribution of 105 species belonging to 27 families and 69 genera in the study area was established. Among these species, 17 Caucasian and one Azerbaijani endemic species, as well as 12 species classified as rare and “vulnerable to extinction” are divided into groups. According to life forms, 46 of these species are herbaceous, 31 are woody, and 11 are semi-woody. Of the total number of species growing in the forests of the Gabala region (105), 31 species are medicinal plants, 19 are food plants, 32 are ornamental, 10 are dyeing plants, and 13 are industrial plants.

Evaluating the Efficacy of Selected Plant Growth-Promoting Microorganisms in Optimizing Plant Growth and Soil Health in Diverse Soil Types

Evaluating the Efficacy of Selected Plant Growth-Promoting Microorganisms in Optimizing Plant Growth and Soil Health in Diverse Soil Types

Adsorption-desorption mechanisms and migration behavior of fluchlordiniliprole in four different soils under varied conditions

Utilizing infrared spectroscopy coupled with batch equilibrium methods, the adsorption and desorption characteristics of the novel Insecticide fluchlordiniliprole were assessed in four different soil types. It was found that fluchlordiniliprole’s adsorption and desorption in these soils were consistent with the Freundlich isotherm, exhibiting adsorption capacities (KF-ads) ranging from 8.436 to 36.269. Temperature fluctuations, encompassing both high and low extremes, impaired the ability of soil to adsorb fluchlordiniliprole. In addition, adsorption dynamics were modulated by several other factors, including soil pH, ionic strength, amendments (e.g., biochar and humic substances), and the presence of various surfactants and microplastics. Although capable of leaching, fluchlordiniliprole exhibited weak mobility in most soils. Therefore, it appears that fluchlordiniliprole seems to pose a threat to surface soil and aquatic biota, but a minimal threat to groundwater. Synopsis StatementThis research examines the dynamics of fluchlordiniliprole in soil, an will aid in maintaining ecological safety and managing agricultural pesticides. The study's comprehensive analysis of adsorption, desorption, and soil migration patterns significantly contributes to our understanding of pesticide interactions with diverse soil types. The results of this study will enable the development of environmentally responsible agricultural practices.

Deterministic and Probabilistic Assessment of Failure Mechanisms in Geosynthetic-Reinforced Embankments

Geosynthetic-reinforced embankments are subject to two primary failure mechanisms: bond failure and rupture. Bond failure occurs when the critical slip surface extends beyond the reinforced zone, while rupture occurs when the slip surface intersects the reinforcement. For a specified factor of safety and reinforcement length, there exists a minimum tensile strength of the reinforcement required to ensure bond failure only. Increasing the tensile strength beyond this minimum does not alter the failure mechanism or the factor of safety. Conversely, extending the reinforcement length while keeping the tensile strength below this critical value may lead to rupture failure at the same factor of safety. This study utilizes Monte Carlo simulation to perform a probabilistic stability analysis of these failure mechanisms in embankments with varying soil types and slope angles. The analysis evaluates safety margins in terms of the factor of safety and probability of failure. Furthermore, this study investigates the impact of cross-correlation between soil strength parameters, demonstrating that realistic values of the correlation coefficient can reduce the probability of failure for both failure mechanisms.

Assessment of portable X-ray fluorescence (pXRF) for plant-available nutrient prediction in biochar-amended soils

Portable X-ray Fluorescence probe (pXRF) is a tool used to measure many elements quickly and efficiently in soil with minimal sample preparation. Although this sensing technique has been widely used to determine total elemental concentrations, it has not been calibrated for plant-available nutrient predictions. We evaluated the potential of using pXRF for fast plant-available nutrient quantification. Two experiments were conducted in soils treated with two types of biochars to obtain a practical range of soil pH (5.5 − 8.0) and organic carbon (2.0 − 5.5%). Biochars applied were derived from switchgrass (SGB) and poultry litter (PLB). The first experiment received biochars at application rates up to 8% (w/w) and had no plants. The second experiment had up to 4% of SGB or PLB planted with ryegrass (Lolium perenne). Linear regression (LR), polynomial regression (PolR), power regression (PowR), and stepwise multiple linear regression (SMLR) were the models tested. Regardless of the extraction method, phosphorus (P) showed a strong relationship between pXRF and several laboratory extraction methods; however, K prediction via pXRF was sensitive to the plant factor. The optimum soil available-P corresponding to the maximum P uptake in plant tissues can be assessed with pXRF. The LR was inconsistent for calcium (Ca), sulfur (S), and copper (Cu) and non-significant for magnesium (Mg), iron (Fe), and zinc (Zn). Our results showed that pXRF is applicable to estimate P availability in soils receiving organic amendments. More evaluations are needed with diverse soil types to confirm the findings before using pXRF for fertilizer recommendation.

Interpretation of Soil Characteristics and Preferential Water Flow in Different Forest Covers of Karst Areas of China

Soil hydrology seriously affects the prevention of desertification in karst areas. However, water infiltration in the different soil layers of secondary forests and artificial forests in karst areas remains uncertain. This lack of clarity is also the factor that constrains local vegetation restoration. Therefore, monitoring and simulating the priority transport of soil moisture will help us understand the shallow soil moisture transport patterns after artificial vegetation restoration in the local area, providing a reference for more scientific restoration of the ecological environment and enhancement of carbon storage in karst areas. The integration of soil physical property assessments, computed tomography (CT) scanning, dye tracing studies, and HYDRUS-2D modeling was utilized to evaluate and contrast the attributes of soil macropores and the phenomenon of preferential flow across various forestland categories. This approach allowed for a comprehensive analysis of how the soil structure and water movement are influenced by different forest ecosystems and infiltration head simulations (5 mm, 15 mm, 35 mm, and 55 mm) to elucidate the dynamics of water movement across diverse soil types within karst regions, to identify the causes of water leakage due to preferential flow in secondary forests, and to understand the mechanisms of water conservation and reduction in artificial forests adopting a multifaceted approach. This study demonstrated that (1) the soil hydrological capacity of a plantation forest was 20% higher than a natural forest, which may be promoted by the clay content and distribution. (2) Afforestation-enhanced soils in karst regions demonstrate a significant capacity to mitigate the loss of clay particles during episodes of preferential flow and then improve the soil erosion resistance by about 5 times, which can effectively control desertification in karst area. (3) The uniform distribution of macropores in plantation forest soil was conducive to prevent water leakage more effectively than the secondary forest but was incapable of hindering the occurrence of preferential flow. The secondary forest had a very developed preferential flow phenomenon, and soil clay deposition occurred with an increase in depth. (4) Moreover, the results for preferential flow showed that the matrix flow depth did not increase with the increase in water quantity. Short-term and high-intensity heavy rainfall events facilitated the occurrence of preferential flow. Infiltration along the horizontal and vertical directions occurred simultaneously. These results could facilitate a further understanding of the contribution of the plantation to soil amelioration and the prevention of desertification in karst areas, and provide some suggestions for the sustainable development of forestry in karst areas where plantation restoration is an important ingredient.

Evaluating soil thermal conductivity for buried infrastructure: Impact of water salinity, mineral composition, and moisture content on heat transfer

Thermal conductivity of soils is a critical soil property in geotechnics, which provides essential information about the soil's ability to conduct heat transfer. Erroneous data can be responsible for the inefficient design of buried infrastructure systems that rely on heat transfer, such as buried cables, piping, and geothermal systems. There is a lack of fundamental knowledge on the soil thermal conductivity under in-situ conditions factoring soil type, alteration in moisture content, and salinity. Our research aims to address how groundwater, flooding, or drought can impact thermal conductivity due to moderate-to-high soil salinity levels; as these may be critical factors to be considered in soil thermal conductivity testing for infrastructure. This study investigated the influence of salinity concentrations on soil thermal conductivity, with potential implications for areas with a high water table, rainfall, or flooding events, as well as offshore wind projects. This study accounted for variations in soil type and water salinity concentrations when testing for the thermal conductivity of soil. Twenty-three (23) experimental tests were conducted with a resulting 36 thermal conductivity data points recorded. The results were further analyzed in comparison with data results obtained from using the current industry-accepted methodology, which does not account for varying salinity concentrations. The results suggest that sand soil was most conductive when added with 15 g/L brine. Further, the salinity concentration or soil type can increase (silty clay) or decrease (sandy soil) soil thermal conductivity at varying moisture contents, which could provide a more informed, economical design for buried infrastructure that relies on heat transfer through soils.

Nutrient content, osmolytes accumulation and antioxidative enzyme activities of sandalwood under drought and salt stresses

Sandalwood (Santalum album L.) has potential to grow into various types of soil under arid as well as semi-arid regions. To find out the sustainable host plant species for sandalwood grown under stress, an RBD experiment was conducted on sandalwood grown without a host and with five selected hosts (Alternanthera sp., Azadirachata indica, Dalbergia sissoo, Melia dubia, and Aquilaria malaccensis) based on prior studies. After 6 weeks of establishment, individual and combine water and salinity stresses were applied and maintained for up to 180 days to investigate their impact on the nutrient content, concentration of osmolytes, and activities of antioxidative enzymes in sandalwood. Haustoria formation showed significant reduction under individual and combined water deficit and salinity stress. Sandalwood grown with Dalbergia sissoo and Melia dubia showed relatively higher nutrients content such as N, P, Ca, Mg, Zn, Fe, and S, which were dramatically reduced under individual and combined water deficit and salinity stress. Osmolytes concentration (proline, soluble sugars, and soluble proteins) increased with intensified stress and sandalwood accumulated higher osmolytes when grown with Dalbergia sissoo and Melia dubia. The activities of antioxidant enzymes showed a significant increase under water deficit, salinity, and combined stress compared to the control, but sandalwood grown with Dalbergia sissoo and Melia dubia exhibited higher activities. Results signify the importance of hosts i.e. Dalbergia sissoo and Melia dubia which provide suitable growth and nutrition to growing sandalwood by maintaining ion homeostasis, ROS balance, and nutrient content under water deficit, salinity, and interactive stress. Results highlighted the significance of D. sissoo and M. dubia, which may be good long-lasting host species for sandalwood production in sub-tropical climates to adapt to changing environmental conditions.

Adverse effects of Ca2+ on soil structure in specific cation environments impacting macropore-crack transformation

The traditional view of Na+ as harmful and Ca2+ as beneficial doesn't always apply in multi-cationic soil solutions. Initially, adding Ca2+ promotes Na+ leaching, reducing salinity, but excess Ca2+ becomes counterproductive. As Na+ leaches, the soil's Ca2+-Na+-Mg2+ mix shifts to Ca2+-K2+-Mg2+, Ca2+'s function changes, even causing the opposite effect. To investigate the complex mechanism of Ca2+ to Na+-Mg2+ and K+-Mg2+, we conducted an indoor soil column experiment using saline water (4 dS m−1) with different cation compositions [Na+-Ca2+-Mg2+ (NCM), Na+-Mg2+ (NM), K+-Ca2+-Mg2+ (KCM), K+-Mg2+ (KM)] and deionized water as the control (CK). The results showed that NM exhibited the highest crack volume, while KM had the greatest macropore volume, with NM having approximately 15 % more crack volume than KM. Notably, only NM displayed a more pronounced inclination towards pore anisotropy value of 0 when compared to CK. NCM and KCM had higher pore anisotropy values than NM and KM. KM and KCM had more cracks angled ranging from 45–90° than NM and NCM. KCM notably decreased transitional macropores < 5.5 mm in length compared to KM, with no significant difference (P > 0.05) observed in widths < 2.5 mm between KCM and KM. NM displayed the shallowest macropore distribution and the highest variability in macropore length among all treatments. Only NCM showed significantly reduced variability in both macropore length and width compared to CK. In summary, Ca2+ exhibited distinct action patterns on K+-Mg2+ and Na+-Mg2+. For specific soil types and cationic compositions, Ca2+ may not fully exert its amendment effects. However, Ca2+'s effect is soil-specific, necessitating comprehensive studies across varied soil types.